SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e758dbe44283f08d4dce9c036d951246a84106a4113a4720848fd28042332c2f' 
  AND token = 'PWH3HnmaE+F6EW3CqdMpnFsXxk7wYPrQ0J0sUgv9ueE=' 
  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"
    }
  }
}