SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29960e942909e20309ee0f1ab6a064fd0a54deb9592ec6bae2c4217cbb9d7ccc' 
  AND token = 'E6HVw1ND22t/QnZ1r+VLRpBOmyYh+hSA2qmvWD1OKAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}