SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e5409e99f5563fa8a08a6b7e983ed7c85b8a9672db28fde34a968fad702c1540' 
  AND token = '8jKUSGRwbOpf/PEhLSMfK8WuwMizgNzUqk3qP1IZXMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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