SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '457535b349bb091654b507c5d8e8b3ce7a28ef9ffd85dc495786adf368c4c143' 
  AND token = 'BKvOBqLT8GkpHFj9Nt8/C0yz+XY66VJxL6Pdq7ixMas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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