SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8359a2fafe4888169ed9145e3fcaba2c45e58e7fb5455f68148b5bb58d76cc83' 
  AND token = 'tzyPLMyWCWbPBXzKhRuq7o61xQ9Yb8VfrUDZ4jNYBFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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