SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '752c87304b7be460b536a8462e7a207d420f95c1efc232fad40a8e59fd9378e0' 
  AND token = 'nfe8GlLgjQFHQFe8J2Aojv9oyPI6cpiriH0C4VgKrzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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