SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a30ed23f95daf577864b55c2f9e72830550c439bc3a033dbc58cdce31041824' 
  AND token = 'HDqIKw6jfrNL1yOEbrbFpJUzGJwkhvagZj229yT5GBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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