SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a0fef5bb865fee58b2d8dc87fa820d470518cd67388756f1bc5042c91a60f8f' 
  AND token = 'Br1vv3WafUx+vghWSKDHRCUPuS5l/fYKJSXZX6txq68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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