SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc328bd38548fec97c26c405fcba389db6eb55a6321ad14f46a5499bb619a7e6' 
  AND token = 'K7DGpIHMXSRXXTt7LcvpMeTkITduDfAXqZ0sgOAWl4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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