SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82f9998244380b3c6b4806229b19d9805311ad54e26b90c61417388504bbb1cb' 
  AND token = 'DP7jxJI8Lw/VenJ6JU+BQ/U4ZqWrnKhdNBYJHzcm3Pk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}