SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '39ce9eb8cbd5cd278c750932e159733d7df7942f43547906dbc653f06ade1544' 
  AND token = '7hdSRIAgtS7NWawL6GuZWR57l1sNjUxRdqO45B5OQQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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