SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b52825ed1f41ef3c0ee8d47f8c7019f2c8436af1f625f1e6ed04e30e3c282b91' 
  AND token = 'TOIKrfXmfjsvKNYBQxrNdZZdCIiOFltBALECnrn017s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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