SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'cac75852f62580945dd5f827105dfa4b0ca989ef0869e1bb23d5d8bb06fea8ca' 
  AND token = 'p/Bq03UPpvJYGo3gH6z/DXgG3H0/IilaW3XJZK+0e6c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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