SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd3d031213a012734150a5032d9f220861de6d5fc157dc814992702d66cfef55' 
  AND token = 'A4cUyMwc8LbWruZ28KJLidYVR554HpLtm8DuBznWOOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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