SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab8b0da6e356e9996e07f0dd74633f83779c0fabaa92dcd93e5e01f409a68817' 
  AND token = 'sVI+zh3t/zS9KZusvbM2stiWsoKvqSrgwlFM7m+rY8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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