SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f434243dc1f1cfd0ecd2f561d4fcca6528c47264f7bc6f53beddefc691195a1' 
  AND token = '54a3IAFdf+nADx4VtLpszBrZ9xAW8GbRB7wivHpqd9A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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