SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e95d21cc834ec4da22410238377a051e0303db9fb414f921f2daefe1c476f310' 
  AND token = 'SoTjDUFXz7VbDOsUVnvquVyfxs54oBRGVwQjt1iu6Ao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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