SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '691b6677754685020be6fc365415fd64618f276ee4246a10e87cd79e0666ee0a' 
  AND token = 'Kci1T9OFmrgpytr1dCwbMAKS8HLw1JfC6zlhaclh/SY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}