SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2359896d96336777f6032080e9d40eb0d7d0c62af024f961c23196a04dfa41db' 
  AND token = 'z0yQ+UFakst8iHlk8Lgitem3tkkFPf8HRvUsrm0QmgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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