SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '833ab9580ad9d849e09d15acfb860e86b0088c4cc08169691606daa9482f64df' 
  AND token = 'TPNawBNiArrSGko8HRHE715YvIBh0RMdyGBoFpOxyA4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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