SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db7cca0c2d417849e2977cf958c16e3217858003993b4aa13df2d6702a10742b' 
  AND token = 'Sz/oxV5Mm/NhgTneuP486RdgrHlGI8iA0/BEhABfw58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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