SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dc6d2bcec0d5f4bc4cee5ba0ecef768e9a29e98a746b8fadb1a05859d208de00' 
  AND token = 'ijQ3SfUb8tYEz7+Nn942J/dCd0YLE54O4nS+gX8GKrs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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