SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9a128cda77f1a6840b36c43e8f5f953db50af3634348a6e59ef1ce5c0eb4112' 
  AND token = 'hR6Ebb/dS4mfjXaFI1CjPMjd/T9ns90K2dfRmeNOsS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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