SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d3ba88d7966d460dff98d274bde7a2245cbdfc9946e1663843a565415371761' 
  AND token = 'ZHpzG/XRfslfWrgXklb3HbBq40dzEbobVu9jxSg/JI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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