SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f3c028123e5d0f21ddd50937efc86aa267e2d52985d5621e75b81c7eac9b70f' 
  AND token = 'u/26WiPJPhl+ViRAKd9pxiBCQK9jgfZoXMxMLvEfR8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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