SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a13c415fd5ffa9166ad978b8d9a0f7175e2fe99f53f2e1685404b8bdf9fd192f' 
  AND token = 'Jt2WIt71ZvOTYnaRGkmGdRMinqy8RYcBhY40b4HUpBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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