SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '116c573ae777d200140a8a30628887494f53a699baa64ccf1f41830805c52bb4' 
  AND token = 'D14aBpdUeTAFMLbnz6gsityUEe2IAhAhg3K7WQkkpcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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