SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '38dc6977f6076a1621178803cd8ec01fef2b8b498812f5321d238df04b7de52f' 
  AND token = 'EsFOyn1wPWDpuzVYxdE6IH0bKpYDgK278AopyBc/0w4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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