SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78ddb8743a73c025c9ab7bb3ed6e4cab100769a504d5f0d0e95a5cf362e196f3' 
  AND token = 'wSvJ7xHHphbKjwpfepC75XvNfDUbGgCUhaqUnLQ/EO4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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