SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b6701cb1726c65f6cd538f6c041de11b7075802c38fc95924cf6c3e33b07646' 
  AND token = 'pcsDuUJ/tk7EM2H3Yjlm+1wW8DEBHCzCmCVr+g41LwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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