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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfc28b5be2e66beec7a4fa0736b610588f4f2604ede6a5ff615b16190624f48d' 
  AND token = 'ujHvfcAJmIrLwnLpGYRS1/Xikj2s5HZfLhtWWWDwNFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}