SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bd4ab1692d5e5c64c0a9d26af2618cb024de3f970eccbb652926fac2527980a' 
  AND token = 'xW6OOrlzZ5FQzRGlqNbztK2E5Sea7vTGZRNPBo/c9Rk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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