SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9638927b865ca964e8ea33b504702e21f1d27f9e86529857d88af18053f1a2b' 
  AND token = 'RbFQwjiK29PrPwTj7XMYH8zq/3pmufnfiPvmZMOqx/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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