SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c9871ecec0f4e5e8a1c626272fe88a81abd134ea2a96394fbe1bd2a4284ee8f' 
  AND token = 'bneFNVjvf6bSnnNRgr7a8mEFVNNkZW+dWoPgsnbI0/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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