SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6429d232069a0010715c6a86f735dccf879c8ebdb2d1196815d8d7b746866133' 
  AND token = '/CzqCR6pej1fv+NZEhbunEKu8VGT86MArJZKnD53EfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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