SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd61406266b5f33c0d0c98391da7866187ef58f60255ef0c392b6babb97c44f9' 
  AND token = 'pDAFHyUyqI3JxWZfOIz3ssjuQw44XapwZ7JMVTIPU28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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