SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '593d06a52aceed909436dd1f7fd6715a98a504648b7fe8fe7932d2c93dd12d9e' 
  AND token = 'IiPoXjrHMtfFgG417HO7xmYe5xC8osvfgFkAWAId4w8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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