SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4e62a194e0df06b5f95862016fe4d9cde9d86ca4970c7528f236eb658544ab74' 
  AND token = 'alLw4Fp06lMVsoVoajXKyq7diseB9mwmaZQr4U2VNvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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