SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6f7efbb805e3bf84300c59784667db83e5ad3f02aae4357ca9b221d2b3e7731' 
  AND token = 'dzfH1Jj5EW2D4elRF0xBCH+yyr4z7tWJn9PcVTD75A4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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