SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9fed8d2a71b10ff528813275d6fbafe8b23601d9635aab989bd3a5ee41b217e' 
  AND token = 'xuensVHHDNkM+1RZjVe7btLKU1KFE5erZ49phUp7iL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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