SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a6b1c4bde59363196007afe362efbe355cb7d090f73b5b3ec4c791ee354bc673' 
  AND token = 'Lml8kiULmIiY3IDF8mNiTarkuGwOU6f00pDvhgZRx3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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