SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52c8e2e036e593ba0733bf96e4cb757970342356849a4af232f0a1bcdd7d8015' 
  AND token = 'R+Y0vObIgxdty0j/lP/0K0V0v0WDOH92VZZcwKjnJNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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