SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8115c13c41b228114cd5f7a805533e7ca9639a024cd464b4d1bb752bf75028e1' 
  AND token = 'UJkfNzZRvUyFUAjpil2DRmlAHUCkSk5fz4hR/qvmHLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00097

JSON explain

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