SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '68376be4172b04eb796ac63dcb427a2e16a6e226c9da61cec511528d8d8b2902' 
  AND token = 'ENzAZ9pqGXvqfISs5jV2jV15FLiK16EWrgb/V8wqn3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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