SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4692f98af151f1dbdcf07f22bd10dbd48c4c917765a2833c340b6102d442a8f0' 
  AND token = 'fSauML5J3ICHMfN/IFq79DZ2WictP1XdQG7kfr59PAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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