SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4c35216ef5f82c7fc98e43f3553deca59ef49bc54873c8826e3683cf0788edd' 
  AND token = '+a+gq/zFoYCgF9RzGwUu+aihhFkxpEBVWZ00ybVeojg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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