SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6b51af0772f6166912f483dd6d7054bcc1568a5cbe2106fe2a1f348762461899' 
  AND token = '/RRHB8ArtWiPZ+jUNuYktW7ARKOUVCADoIaIP+s8OkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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