SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0381eeeda573c6c0f46951ebd3ad500f095194a34c2674b9bf5e50e3b331af4' 
  AND token = 'x2RE34JO8Ea/OUkMcxUE0/F8eKGfDLWU5nacsSzuo4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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