SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7c6b7267bf611c5b801c8a10e99170c53fcc28521300cc015028b192bcc26c2' 
  AND token = '1tjj5XC16qsAZuTHXBY+vWK0utTi1o5murgcSUEflG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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