SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '311469a3f752d66133909e03ed6afa666bd221933c1c756ca16b89399275d25e' 
  AND token = '9N5CtEgHG42P2xl2IJjmUTqUOcL51aKE2c/R4ywhuPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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