SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e29339ec275482833d2484f44b3e76e77b832fea8c1b7207a720ac55496c7c8' 
  AND token = 'p6QZZgjchwb+nYv4zj9hipGeQaYcgBPV5xBf9jw09J8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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