SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89dfee92fe5983f08f4f11d0d3bde03d9d8adf4464ac2a4d8ae1098a4c0dcb88' 
  AND token = 'vPDhlkiInoxiCiMh1xzfVAMT0FFOmwNbVkCZKBbtPuw=' 
  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"
    }
  }
}