SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b152cd628a28fd775ce6b1441c03582795ba83204041df2113f9571e7519551c' 
  AND token = 'z5g1Eu+xg/8GJUBBO/+zhlpg7RCFsEl5v1O8siIV5Iw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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