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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f73bb1f91cf9e5600c7eda1e1ce5c8835aacde10c6c67aa31d9f2a729d7dce0' 
  AND token = 'GCSObaxZz+qsvT27112d1Ac0lH0tKzZ9K7OOXNWrPy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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