SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98c3f9873fe7241bc13db6527f1fe4dd89820893ea8057bf540714963b9f1208' 
  AND token = '/2wA+IUtvQn4CmvfyPwRnSGL6wFW4hjo2RrXhiPHyIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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