SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3c8b93b50d248b6a4afa25a9d7eeb4b675bbe889bac9cfa438cb748e26a2ce24' 
  AND token = 'kPtaPTOKWeXBGyAvgaoT3tI2z0QmIxwTrAlBYyB8Xos=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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