SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b8191551c4df291b992d1e924f11e642c88ccdf8a57884793cd04d216762fc1' 
  AND token = 'j5eUYrCNadNZFqSIRAXvhjwKOnSEEIKNo6w/DhdaHvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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