SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '644f8e6293ad00f5a2c0659a304e1e0bc8c821a9fd2bff378f28951341c44816' 
  AND token = 'mQKP/scbFj1oX9v5g9Jc+2ELggtu1ZozAwNfk2rhhKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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