SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '063b2e0d0f7e832b17127d80834197c356197837f44479f2d6ab3c302e720ff2' 
  AND token = 'RMWbjLaCUwT6ZO0NHAsAjYBZt1PRFQyEErjol+wuic0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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