SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '0c48408c9d72cbf6815d472021869761f7bb8bf98776b8456283682630b98d3a' 
  AND token = 'rKD8wgI+/RrMupyBPZ0PaUeek1OVBN8aQ99GYFWtzy8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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