SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65d2449e6204f8ece33c57e6805419fe2ddfc69cd3770bd00cca2a46abded4f5' 
  AND token = 'XAG5sjSTXnY6rw3ygto6KkIK+hAHiyDrOrCnZaE0qi0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}