SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f2bf607291d16f72f6ae39fc8e9bfe82ac10a1f55e21536a91aa3f55b848273' 
  AND token = '0+WrA+faVKkcR7YhTjUV+Al56BBcnKExJH/v5LZClU4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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