SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a209344cb4ae23be7fb36e642d99399b310e3e7037c070b073ef4ddffeef2df1' 
  AND token = 'G4mKVHvmkxYiqkf+AP5DnQ6CgWlg1qiRAlu68LXW5kI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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