SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'cb040fa059f621df36c6e350e76d44517861837a640b53aa5caadc1e77616123' 
  AND token = 'LPg7R4Wrq9+EWO7pwY6tVKC0lRL4jQvR+BVd4nhM7Xo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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