SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '771e3a7d5f15711a5aea2f0f75a1cc8694d5395454f76a1ac4de85bbda6e1c23' 
  AND token = 'MN+Du8rQRP+20IVCdhJ3nnoXvGdIVxxxicrigI0P4GQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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