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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc99a07a9f0f50a61caea51d569bc5d4422cf0bf31b07dc286ac506f15393c04' 
  AND token = 'ikDeFJ7Fg+FkJFeAeLkM+RT7iIlh2RmjssG9MO1XaH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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