SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a0f6a9dda4b5eba56f15197c9ffd837377bc306c8b9e32c9d596701cff6836d' 
  AND token = 'z+HgFhdl+Uzjd5f+ZR2+xI6WXVFQ9ZTnZ7tYsxWh4vM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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