SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4b8c4546188616824a003c9e96ced183b48d06ff3ff6928e599ba27cb1985b6c' 
  AND token = 'LkNCfqekdPPB7PBsJMt5AEf6V5z+u8boVP1fg9YNYlI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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