SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c7b5507c09adede18c88455c5cc9a4b5becee5e8497b18de355f9baa0c69a3e' 
  AND token = 'gvCHo6LRnKwQXrSfEz8pryk9SS1f8VNwXn2r4R6YLok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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