SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37b459d44bd3f81a9f99ff964b7830561f28dc76952a45f85885dd26257470fe' 
  AND token = 'sVtL7ulnaZ3+PtsnbfsQTP36ppIhOMhWMW6zedZIZ70=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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