SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d5d788c687e26c45395118546311f59dee1f53d4a5470edac7002c5231cb451' 
  AND token = 'ZqnRI8M5+yFqXQlJNO4xixP0zHRDaX+Vomg0bNzXfXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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