SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7b4405873da6b38176415544cb6ad37724bf5f8b6ca5c013a34198d5c872e94d' 
  AND token = 'zLwLKbdC7JWec8sBfpZVdzP/lCMhd4fYLSmMNf9HLhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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