SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '97964c5545d0d4de6e5e5040032b6a2d2610cb804582160928c96ffc95da05ba' 
  AND token = '/UD+wMQsKVTLd0nDVA/YFBTez75tTebj4ekFhRWiHMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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