SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f67b6f8454d412c1c5878102bd1d91b9b2a641084515f53d829fba2eae120ad2' 
  AND token = 'lIhzvpz6+1jkHVe/fGzwxgMrZRlFFBun89Lx5uJvVNo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}