SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8e00783c68175f97e740438b22859870348567f7b2da71c816077b3931c93c4f' 
  AND token = 'SRdW1PJ1iN+jqhXmzD3g9rdyueIMC4lI5NWL2BKjh9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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