SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '234586e126b5a320412d0f873ba560e71010cea164084ee5e3d85e10b4ab8399' 
  AND token = 'bnPtmWuTPfgEQYbZkxTg8OJETRUkSzcrqFwGR5f5RVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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