SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '42fb1a91de80c6d79ca06deb577aeeac007d34d9f8f45fbda387361cd7b4c70a' 
  AND token = 'jkHcLgDYktDOq/VsLKw41poxlTiEXYUzYO8Q930xsfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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