SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fd4b168cb2f3f9260f8e873cbc4924170ec4ef3b9f273d0306482819c472b680' 
  AND token = 'Ylq+VOMQSUW+Ov2ceJzD/zIOwWduw8KlJ0uuJWaMDdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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