SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77821f9ccb892ffbd3a6003f06b7517911d4b87aff919243a42f3b3d81a0ca39' 
  AND token = 'SJSr1WnbqSizDK7RDyNMP8JBjPCxhQVaA2PrXAf71dU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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