SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cac1d4c5b59e986424dd2346b098852caa4cac38b8aed9b8d602dfb263f32b86' 
  AND token = 'dVqAPvf7zzzER41Z7KzM1SYW/mBGfm99J/IulmnGv98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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