SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24d692f2edfcad17346d9d13de3128b6ee4a5f5219c5279e795b1f928d4e551d' 
  AND token = 'Rf0/LODT9wouSlLfG1Ph1oihbiOwBy8/GkyEklM56h4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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