SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54d23b505359664929d6f2f28e17cc8187900a6b66aa0c312d7a01e162de4e1a' 
  AND token = 'S1joMdgx29zAiTRZKlYFK2/FCaaR64wEUozZl6eqo1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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