SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46bfa4bdc2ff0e08af1356913a5f4b1d75d1e89d5da69461c208d83fd0a01945' 
  AND token = 'uub1MtjB1bU0UQ42d+6KQOeGOZvo9AhAD9bhsoKvnBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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