SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '00f2a51a84599385fb257361a39b8e0af465fdeba5f213c43704bee513823dbf' 
  AND token = 'eB6aMT6C1vJq9ESXnQY7rUln/UckdQT+2x/TD5/YJjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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