SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90d87a8303d75485ca4b9bd227742a22337bfb593e8caac8af35c89f82cbeb53' 
  AND token = 'PJDpWdYtrv64cZcoTxheSj+HdNazp7sZkKfyikPV8ew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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