SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4c4607fe1694151a6114f756a7322999247ab22ee0b3e05e7cbb0a4a9c72cbd' 
  AND token = 'jp6zavDsOIKbu/uff8Yq2hKE1utwE5cDaMPY1SKIO0c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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