SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34731578f43df19e97651dc4a4030636ba407eb4d6b3724a823075c551237def' 
  AND token = 'Wi0lOUMKjz53Y/7wsJoni5lKywQzx/Lmjrn0TOg61Zs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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