SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5743780b835faf511bc65a83632a2594c163d6fa680a4d90fe419e42cf038efb' 
  AND token = 'DfgMq0tKPa1pNkiK6xlnVk2WRxbxYljvu89Dh38ck5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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