SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '1c667c61f2f4bb510c54e08ff1540ec0ac3a5608384212f5cda229d42a33c373' 
  AND token = 'DDS6+9IniyaWCx8F8cvb1p6fsXj2LyAAYoZV3FHj1eA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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