SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfb533fe234b352d24b42b9e4ca6c96d86447851e7a879954b3965057ef31241' 
  AND token = 'xyxaBTPsvuUtcRPxATdvN1vetwmJ/h/btIhxwzqdWKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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