SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9763af03a8531d8076b5f8f2e0bf3b1b28938eaa0beec8813da476147521bad2' 
  AND token = 'e04sVLHGDu66Ds1H0lIaHKAPl9TuOfIg00SxPIEq68o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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