SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '789d1dc9c95b65bb989169f141e93763d0492437dc00e9fea6bfd437ff32fbe4' 
  AND token = 'HWEa/UCMKMlL9LsdegzH+v7WMOwhIKhZCqYz4EQ2RHM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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