SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51599559415c9c83e7775c1c6d674d31e92698d1344c5affdd1861efe63d8ca3' 
  AND token = 'B5dt0ylYBAWcUmKveZa2/3XnkF9w05oxIdUFuay487A=' 
  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"
    }
  }
}