SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20e2716db36e960d167f66a9020d3d1b6f00f779731183678875870b295355dd' 
  AND token = 'WTY7thFb9lYprguw70A9gKrng95DmqVy4gYLxe3tY8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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