SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3acdfc049ac44b73fe40eadaa77c3d60c1e46a3129c924511cfd5ec927ce1ad' 
  AND token = 'SgrsfmrHBo9aY0zhYDAr2aQrNs1oAcr92unExvsRjko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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