SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb65d296155cedf4afa87d80e3dfa366fdb9381850b3ac9f618642a8e830ff4c' 
  AND token = 'jhfSevIqc5EvYXnZ12xWp400ZWEyzEluzudQ1vnaUP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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