SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd434dd8553fdb0fd54e0d8b89e2b39136a997938d25bc05650cfcea3b9fcf446' 
  AND token = 'dSAHxtXSA5qZQYeQEKyGEbCiyzBKF2sLYTelhT7wOGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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