SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cee760689bc4bedf17e863ed629ad7daf0d6c1ed3b5ad245e17207cc2570208' 
  AND token = 'R8D/eIuJMUoBO8YY5vdag6qArLDRffS30JgztVXBP0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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