SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '86d6858c717a1594b5d5d053ea047a53e3b8025e576c080142e9c366c371d0fb' 
  AND token = 'WK7+XF+k9VDI4paZwfvrDbSx6XJ8/AvnXLz42RfP/N4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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