SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f81ae31b242a765fc7d5d9dad555c145530049286ecc124ee37ab03545c759f9' 
  AND token = 'xZhEzzrV+UCw4mZKWhiwIGfhHvoKiU+8QE6/Y4ZhtZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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