SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70ec0591796b38beb1d00d3816465b239a3376500998c0c21802a844973bef0f' 
  AND token = 'sSaedBUF8U0JQVhwbKECqMEe35sb3kSuKP4mFkWqUnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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