SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '502508f49f2ddba879e461b5679ec076f7be6dad2eec06278d8fe2973cfdd39f' 
  AND token = 'Iv9gihxJJ3MfqTyMNmUnq04i2goTccme+DM2k2pTEtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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