SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3745a2e2874a1aac7bfeda2edce66cbb20cd13fbbb5775886efa0cc0bde2a8d' 
  AND token = 'bY6J7R5wYq4PcY4391z7pb5EjsibZx7D64CN3BJdSyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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