SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c47324cbe2abc2cfd7ab5c5471dfcb2a72609af6e3d5f6f5f3ddd8b61dbf84fe' 
  AND token = 'MQkaJdGo9lURVWX1hARHBr82zRzQkEvUtGyx91LpfLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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