SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f20ab6d7637f7a551dbccc2751f50ed540ecfdead87870f52bdcc810c1a9e2c9' 
  AND token = 'abwZGXw8ivMBkYOwdzcDgsL2d6SJtOD7gydDCPi25qE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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