SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd61640c6724304d458d8c23f559442e490be84e7f7f81c5bb68bbb8774d5ea1f' 
  AND token = 'nhY9TJHjY+j5kyP0gSAx0AkVSVClBKS/ubm9m68dhns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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