SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '900b45807a5c2911bee0697728026abd21468af9cca33d8efb903dd0f9236b74' 
  AND token = 'g+VQARS4C/0F3ZQn1xn60WDUt6FnJBpMhr+VNCmuVJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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