SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da5cad83e20012dbb420e269883ac577f34afe44740ef46cda0cd4e17e3eb3f5' 
  AND token = 'ZVujxggLigNJ5ExYwzGeGzkapYHsYSuUgdV+fLemlHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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