SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abb4b84fea506950accaf06faed2d6bcb4a97737a1d89b328b8cdb0ab68b33d1' 
  AND token = 'mopIMTyVZIQWkoIdnzuZD99NkGjs0r4UAkSJDfgDnxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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