SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '55a2d6d748331e5bacfd69d60bf709c09ead1029f971c141d26fa131702d0cc0' 
  AND token = '/G9hGGC5CZcwSnSDtkvVtwnqDiXUM86TJMnWEC/C2lE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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