SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5111a6c4b5046a12bd73bb8dea4612f99e159535550b0d7c9f74a3b7692498c5' 
  AND token = 'EKuiBg/mXiYhP/GBi8PmZewJSTtVbyq3EfZEkHK4u/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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