SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82ff0aff4bcd4efed7de5ac714682c156475b3179fbf52a729659ed19a39042a' 
  AND token = 'LnUPZqVTynNOpJ0QAqgZIxilZ9yH0q8Mq/s4w0t37SQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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