SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd3be22c28a23accee56416747dc4e9932abf2376181b9598f98c0460fd0e4d1f' 
  AND token = 'mYUgceA0jskF0GxnhgL13/Md98eGKtU2adGyScwUQH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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