SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '699daa8f208a68ec665ed5280a70cf7f5da133bab34bd72b32bafbbc55552bbf' 
  AND token = 'eKlMr3VMPp8J5+gN7n8iZaTXGswAhF3ba/BM9uZ5tqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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