SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8834a688ff82dec4bf41eb26b066e108c67100009e52bc937d3aa461cc793aba' 
  AND token = 'MJ5jnSxpTX+kDbVkLSmAKYLEBKvDBbSiGhjBUoWS1BQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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