SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f73859a57c812f014bc63b8a11ecf856f590400666e2aca9617ee90c79a072f0' 
  AND token = '3mLQXkcDmdh+lus1+0w21vhlikCCX9nn2PaGYzg0aUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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