SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c221136f78cc644bf09cee4ed56695510cec7ba6a5433cbd072731bd5112b044' 
  AND token = 'fHYRQjqpb3szR1H9qHGY8zn0xJAE8yfSdfqe2dngGo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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