SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b545214be438f8cbf8d6381948d33f08d6d823673a816e4783550579083317bc' 
  AND token = '9j/+qHBy/zugVO8FU/9wC0kBHcMGC3QLQUDYR/DeFwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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