SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6102c845d782bd876e61d41d0b4ea2014ac419be196c92ed0322388fc3976a87' 
  AND token = 'NUqgzdz4KbwT6UukJuVSWp0r2RE3IbBT/mjfuuTCVR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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