SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55260dfb900c876c5eb8c14af3323b8787e04b9c46080f845ddf513121d76734' 
  AND token = 'yhgqLPJnCDOrthYlzg5K8+2KCzrLY6bi/aH+IahP8lM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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