SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '378841362c605af91e2bd5317cb26248c12d8dffe98eb10b9a5b88d844ad0345' 
  AND token = 'SdGqgovll9N1+CQIZgUlra17h3qq6KbrJVPPwGi1hpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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