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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a040608f0ddc2721ace952f4ebba768dce14a3f80dcaaced025406f1f97ca88a' 
  AND token = 'h6VkcgdRLn3QUF3E0SUY4rjE1EJ9smV183B6qwz6i+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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