SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '438b72763c83b6eab598879d7f9bdaac99f4077d8b8c2f039697fc92918fbff5' 
  AND token = 'Q4uEYgpPIAffOftwu5FKFnly+7gjkS3in0CX4eDKNlI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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