SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82a788a1dc4abbffac74f3adeb2206c20691e9b5c95f595fc5b810453ed482cd' 
  AND token = 'X8kNPQgC86tHLLNji8bT0dkZdrw/s+lJexj3cG31JkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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