SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3236f2d1d7cefb37ebb5face4cf4768151a0286030ce5e7742139fb6b5b242d' 
  AND token = 'YoMIfttPDesFsVhI3qVBjDqhV2Ryho7KFzB1EpjxYbU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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