SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4cda227d03381faa3281549038ec99d70e0d234174b8ae2582a57d2ff35e1bd' 
  AND token = 'aBz/1sgYFiO9wBtkJHXc1hOqIjTmfIDKjPSPJ+N7kqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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