SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f350aad1d1922a0fc6bcf3c7f1ce518724ecc20bf4ddaaa002c6acb401e51a1' 
  AND token = 'KChComjTsPrdqZgxjjNUKL/DRmHQzQikEvsY2o/mPA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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