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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b903ffd612cc700ede5aa7b2d233805e9dea69357e4113b650d04e3fd716c1c' 
  AND token = 'QsFrS2DIFT+ZtpEIbt4qg3Gk4fCtBDqOQgSqT5do1Gc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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