SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4fd3af2680b0645cd8369a3fe1adb69f247f19c1d6b160ca8f29eeada5c6c5c' 
  AND token = 'M4gR4oD8L5Fq8LEpk94Wv9x7Wye2Xgdyu05Hh7IWcBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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