SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c6065ec528476ace030a0002c449f1088d8ee8e65916a8e32ff3fa483de5eaa' 
  AND token = 'urRrKa3AgDUbBUpZqwIoa5mTFJn3YsSe//dOcdO0sjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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