SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b5b8856c480d73e20da046a1371099e7d28a1c4a2d5749a81ff0d9a19d4bb73' 
  AND token = '7B1NjsEwS4woglP/P5ZNudABiLT4v/VZ2YXQ+czsOmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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