SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bf08b9b84134374a2039e174ea62f8e18c52dd8c596040a5c18c802859f6be0' 
  AND token = '4fHh2qDgWvx8anFVUmrghoZjdOsnOzAHmb6r/Bl+1ck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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