SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0378939aaa6eafc8a083bb9eddf62df8fc40f59a776702a1c3aabf2aeca53601' 
  AND token = 'DE0YrlcWIxtos8pYLD+8V+mW6dkA8h0by9/4CbFjOB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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