SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f54ba62d1f2daa3f81585e8f88f8bdc096f5a3f34364585fb26839b9c77ad713' 
  AND token = 'Cqt9m0FQkFqkpgwK+UY17kqA+C6dVI3LNRqWNvhPjWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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