SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc8913e09d4229ba1856db985c41f0ca76be62cf2d30b2d0b0d223a1b3be66c7' 
  AND token = 'pHB+xglYAmSlBjOnWZM7KKZS6aRHQJH3mFHnqqmGVEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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