SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9f0eb38fc996bbeba72fed750b7c10305dbe482705f306ac78a8b100a600c51' 
  AND token = 'QOXpbc+XM/idXQGOFcHdMMk7k5IhjQGdNhffNuzTeUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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