SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '559e9d59fa047086020e2843d6eb91f33b1d59cff48ee3e8f2f26fefc240b80a' 
  AND token = 'ckT1deSPgAq27H7rdRFWRzq7uShzFEoe7nSh7GzpQqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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