SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1e960fcc443721edd87a46aaf338f16c542f99c368fcbbe5931e867470de082' 
  AND token = 'vDChjmGia+lFFqwBvz3zb7vnNAuP8sKzntp/VdipBH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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