SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9817b681f6ee420c147577decd2b8c142901a79689f08a4f18eeb7f41843fe9' 
  AND token = 'MwCgLQsnSvrT6whM6EHif08fvPATbqhcqqlmDz1Xdvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}