SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '724a1db8d3c6af79b156af1e5407bb2dc60985ab574dcde3b35003a77e60fe18' 
  AND token = '3iVeJ9r9OckpEZE3i1heSoFih9E0qeyTHPRCb+7/crY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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