SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b27cea784723f0e92933d5c653d86818eddf36d350690387a80f5ba4e66b4f47' 
  AND token = '7yk9S0vb3ktQQXBpPYBv3KfHzPRaZwrxrhOIVs2hFLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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