SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa76a4434c500b87fa429ef972eda51919da7c572046fbd4c7c0afe6094f8c62' 
  AND token = 'mujZhQWlgpiIYgsbhMwfzyt0qhb1wPKnHmkm33CuIiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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