SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '0beb70c021543353012215096e77f5a2e4e50a65fab8533960ddd99436583689' 
  AND token = 'KUSeAnwp5nAcq+oTQg2cGVOy8IjUfifygGT453vn+ho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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