SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46f16c2eb0baa31180fde13a4a896152ea1e32ae306ad77dd2bbffa7bbca4624' 
  AND token = '4JnBiDE90Id+Ag9QG3+CsgSZpIVoH85wx+9zSzhpoS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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