SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36d337ab98e93d7a475158ab4e475edd697af8b5308859c9ab688fb1bd62bb5a' 
  AND token = 'vRj4kfb7CwLSdz19LWAZhlHeJiu9XE7r5Vp7sRfALcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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