SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6b37d627c4b4795aa7f95d6bc76ee96f0fe013550493bdafdf86c72cff64e2f3' 
  AND token = 'm+FcONmA+LU18qyBJEJXagggarIjeBZf/VzEJ+e9HNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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