SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27a6aeb3318bac2a5e4cb7599401cad2e7edb8caaf20ff9996e0286b7640e1c3' 
  AND token = 'a8mS5twgPU95KCRhJBcWPPXvdV2O0usJHrLOGgYxP6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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