SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b77fe3842e3e4d0b97556b5215b731d9cd61707bcb39c3742b5a2495aa7a294' 
  AND token = 'Y0Fhj5lJ9pUqdVg4y437x1jgeUXDRVQZejZjD/IT7Gs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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