SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '51b18f937c57a667bc3d8a45a35d1a3fc176d5002e2823386a4631776d6c8b04' 
  AND token = '6yOybR25Mp+sELwehFmNp7vfpWSpFK1epWEqFM41Ii8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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