SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6321f56c2127efe88e89efc82af5b2c8d44e245b3d7de3edc0908b9f8e779fd3' 
  AND token = 'Cc8mnydy/HeWeq6sBj1jJ3dANogv0+5QbWbuJAORBLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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