SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc8ffbe49c19c7603d74cd50a50d7fc268f28aadcac26041be5b4ff71a430ee8' 
  AND token = 'rRZE9YRYCXsQqTmOKareYHKanTK5RfSonNa93P5E6V0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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