SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc722343a806522425801a7c5da0df96686157dafed36cf8208f95e6b9f10bdb' 
  AND token = 'hCXBWD6UE+9MpXvBjrkMT4vH25AQ35O9XuUmoAlvUvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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