SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78e8f061e18e3c5aaff5a69bbfa2c787eee2f5c6b0d402ef7f0c8e9c61416f41' 
  AND token = 'YIfkziGnabbR9lh0wnLTiMdYp2LHVssIPNL/Gl1SNkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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