SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5537c2f33a28c9896815546b9ea0fc9cb23db66e4585bda53e6ee32a36673e07' 
  AND token = 'UFvlHOGtgO1ufQbD+JqYcWbA2cnfu2cctYmqe6Tam98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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