SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd639db056f3ba75e9221deabb1ed0cd52cbab4e9fc2ac72ac1d9bc49fd27f154' 
  AND token = 'I3SmenY2dLZmBkM8dbejzIJHWNhTY2PMkhdUDM/K4uY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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