SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23156348bff635f7393a40bd8206a02de29cab1cf5a157abb142fa9ce2d09364' 
  AND token = 'c+BIpIYJFHqJ/OvpVbDdItPF1b+q49BZuYR4pGY2Ees=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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