SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdfc7974e4e685048569b5a11da35a7085b1fdbcb47a67fed0feace8a01c485f' 
  AND token = 'YA2FZuLL97r0nAvbKEzjWN/unJ+JkQePXlng9f+gVFM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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