SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5862d993825d454bd22456e5b204f11eea6502de47f38e0e8d2dec1b8ace38a6' 
  AND token = '7BJOBqpXKfsog3miE22VodHCeKh0fLWq4xD2vOE3RVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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